Vibrating armature pump

ABSTRACT

The invention relates to a vibrating armature pump having a pump housing, which comprises a cylinder for receiving a substantially linearly displaceable pump piston unit ( 10 ). The pump piston unit ( 10 ) comprises at least one pump element ( 11 ) for pumping the pumping fluid and a drive element ( 12 ) for driving the pump element ( 11 ). Both elements are designed separately and arranged loosely one behind the other.

The invention relates to a vibrating armature pump having a pump casing,which comprises a cylinder for receiving a pump piston unit adjustableessentially linearly, according to the preamble of claim 1.

PRIOR ART

Vibrating armature pumps are distinguished by a piston which vibratesback and forth in a movement axis and which is composed at leastpartially of magnetic or magnetizable material and is driven via anelectromagnetic coil.

The piston of a vibrating armature pump, when it penetrates into acylinder, displaces a fluid, in particular water, located therein. Whenthe piston is extended out of the cylinder, the latter is filled withfluid or water again via a piston, so that cyclical pumping actions cantake place during the oscillation of the pumping process.

For this type of functioning, it is necessary for the inner space of thecylinder to have a fluid-tight configuration. This sealing must beensured in any position of the piston, and therefore a sealing surfaceformed is usually a sliding surface which also performs this sealingfunction during the axial movement of the piston.

Vibrating armature pumps of this type are described, for example in thepublications EP 0 288 216 B1, DE 10 2005 048 765 A1 or DE 600 16 905 T2.These vibrating armature pumps disclose composite pistons with a partcomposed of a ferromagnetic metallic material and with a part composedof a non-metallic and non-ferromagnetic material, the parts beingconnected positively and nonpositively to one another for the purpose ofoperation. The connection of the two parts may be carried out, forexample, by pinching, caulking, rolling, clamping, pressing, bonding,welding, shrinkage or by other methods of manufacture. In this case, forexample where one part is concerned, undercuts are provided, into whichcorresponding protrusions of the other part are latched when the partsare plugged together.

The disadvantage of this, however, is that the execution ofcorresponding undercuts or connecting process steps is complicated andis therefore cost- intensive in economic terms.

OBJECT AND ADVANTAGES OF THE INVENTION

By contrast, the object of the invention is to propose a vibratingarmature pump with a pump casing, which comprises a cylinder forreceiving a pump piston unit adjustable essentially linearly, saidvibrating armature pump being capable of being produced more favorablythan the prior art in economic terms.

On the basis of a vibrating armature pump of the type initiallymentioned, this object is achieved by means of the characterizingfeatures of claim 1. Advantageous versions and developments of theinvention are possible as a result of the measures mentioned in thesubclaims.

Accordingly, a vibrating armature pump according to the invention isdistinguished in that the pump piston unit has at least one separatepump element for pumping the pump fluid and one separate drive elementfor driving the pump element. This means that according to theinvention, during operation, two separate or loose elements form thepump piston unit vibrating back and forth. Accordingly, the two separateor loose elements of the pump piston unit are arranged next to oneanother or one behind the other during operation, without there being a(materially integral or nonpositive or unreleasable) connection betweenthe two elements, that is to say between the pump element and the driveelement.

With the aid of the two elements or of the pump element and of the driveelement, which are separate during operation, connecting process stepsor complicated structural measures for connecting the two elementsbecome superfluous, so that, according to the invention, these aredispensed with, thus saving corresponding costs. Accordingly, avibrating armature pump according to the invention can be producedespecially favorably in economic terms.

It was shown, surprisingly, that connection of the two elements or ofthe separate pump element and of the separate drive element is notabsolutely necessary for the proper operation of the vibrating armaturepump. Thus, for example, a pinching operation according to EP 0 288 216B1 or a pressurizing operation according to DE 600 16 905 T2 may bedispensed with, which signifies corresponding savings in terms ofproduction. Above all, economic benefits, as compared with this priorart, are also achieved in that corresponding clearances or undercuts orthe like are dispensed with.

According to the invention, the pump element which is separate duringoperation and the drive element which is separate during operation areadvantageously arranged loosely next to one another or so as to lie onebehind the other, that is to say, in particular, even during themovement of the pump piston unit back and forth. For this purpose, forexample, planar contact surfaces of the separate pump element and/or ofthe separate drive element are advantageous.

Advantageously, the pump element has a first stop for the drive elementand the drive element has a second stop for the pump element. What isachieved thereby is that a defined contact or a defined contact surface,to be precise the corresponding stops, are present, with the result thata dimensionally accurate pump piston unit can be implemented. Forexample, the stops are designed as planar surfaces, so thatcomparatively high forces, above all from the drive element for drivingthe pump element, can be transmitted between the two elements which areseparate or loose during operation. Furthermore, active forces, forexample advantageous restoring forces or the like, can be transmittedfrom the pump element to the separate drive element.

Preferably, at least one first spring element is provided for actingwith force upon the pump piston unit and/or the pump element. Forexample, the first spring element is designed in such a way that thedrive movement is somewhat braked. The drive movement may preferably begenerated by at least one electric drive, in particular by anelectromagnetic coil. An advantageous or defined pump movement or drivemovement for driving the separate or loose pump element can thereby beimplemented.

Advantageously, the first spring element ensures that the two loose orseparate parts are to a limited extent held together or connected,particularly in the state of rest and also during the pumping action orpumping movement.

In an advantageous variant of the invention, at least one second springelement is provided for acting with force upon the pump piston unitand/or the drive element and/or the first spring element, the springforce of the second spring element advantageously being directedopposite to the spring force of the first spring element.Advantageously, the second spring element is tensioned or compressed bymeans of the drive or drive unit.

Advantageously, the second spring element presses or pumps the fluid,that is to say the spring stroke of the second spring elementcorresponds essentially to the pumping stroke of the vibrating armaturepump according to the invention. The second spring element canconsequently be designed as a restoring spring for restoring the pumppiston unit or the two elements separate during operation, that is tosay the separate pump element and the separate drive element. In thiscase, the spring force of the second spring element advantageously actsas a restoring force for restoring the pump piston unit, pumpingadvantageously taking place at the same time during the restoringaction.

Preferably, the drive element is composed essentially of a ferromagneticmaterial. It thereby becomes possible that at least one electromagneticdrive coil or the like advantageously transmits the pumping force orpumping energy to the pump element of the pump piston unit or said pumpelement is thereby acted upon. It was shown that a drive of thevibrating armature pump or its pump piston unit movable linearly backand forth by means of an electromagnetic coil can be produced andoperated especially favorably in economic terms.

Preferably, the drive element is composed essentially of magnetic ormagnetizable material, in particular of magnetic or magnetizable metal,preferably of magnetic or magnetizable high-grade steel. When high-gradesteel is used as material for the drive element, it is especiallyadvantageous that this material generally does not rust or is notoxidized even in liquid media, such as, for example, water. Thevibrating armature pump according to the invention therebyadvantageously acquires a long service life.

By contrast, a magnetic or magnetizable material, such as (rusting)steels, which, for example with a surface coating, are designed to beappropriately corrosion-resistant, could perfectly well also be used. Itwas shown, however, that corresponding coverings or coatings, etc. areworn away due to the back and forth movement or to the vibration of thepump piston unit, and this results in adverse wear and may expose therusting material. Vibrating armature pumps according to the inventionshould be able to execute approximately million strokes or more withoutbeing adversely affected. This can advantageously be achieved, aboveall, with a high-grade steel as material- for the drive element.

In a particular development of the invention, the pump element iscomposed essentially of a plastic, above all thermal plastics and/orthermal setting plastics, in particular even mixtures of both, beingconsidered. It was shown that corresponding plastics have especiallygood sliding properties and are also inexpensive. Precisely the sealingfunction of the pump element can be implemented especially effectivelyby means of an advantageous plastic. For example, the thermal plasticused may be polyacetate, PEEK, Vespel or the like, and/or the thermalsetting plastic used may be BMC or the like. These plastics areresistant to chemicals and/or are cost-effective and/or have anadvantageous sliding property.

Alternatively to this, a high-grade steel may also be used as materialfor the pump element. This material, when used for the pump element, isdistinguished, above all, in that it is abrasion-proof andcorrosion-resistant and is also resistant to dry running and/ortemperature-resistant.

Exemplary Embodiment

An exemplary embodiment of the invention is illustrated in the drawingand is explained in more detail below by means of the figures in which,in particular,

FIG. 1 shows a diagrammatic longitudinal section through a vibratingarmature pump according to the invention, and

FIG. 2 shows a diagrammatic longitudinal section through a vibratingarmature piston unit according to the invention which is arrangedbetween two spring elements.

The vibrating armature pump 1 according to FIG. 1 comprises a two-partpump casing 2 which is fastened to a yoke 3 of an electromagnetic coil4.

The pump casing 2 comprises a tubular armature receptacle 6 which isplugged into the interior of the coil 4, and a cylinder part 7 whichbears via a flange 8 against the yoke 3.

A pump piston unit or pump piston 10 is introduced into the pump casing2 and comprises a pump element or piston part 11 and a drive element ormagnetic part 12.

The piston part 11 is of tubular design with an axial passage andpenetrates into a cylinder 13 which is formed in the cylinder part 7.

The pump piston 10 and therefore also the piston part execute duringoperation cyclical axial displacements in the direction of the doublearrow A, that is to say it vibrates periodically back and forth in theaxial direction.

On the side lying opposite the magnetic part 12, the cylinder 13 isclosed by means of a transverse web 16 which has a central throughorifice 17. A compression spring 18 is supported on the transverse web16 toward the piston side and presses a sealing body 19 onto the outletof the tubular piston part 11.

On that side of the transverse web 16 which lies opposite the piston 11,the cylinder part 7 is prolonged in tubular form and at its outer endforms the delivery-side connection piece 20 of the vibrating armaturepump 1. A supporting ring 21 is introduced into the connection piece 20and forms a stop for a further compression spring 22 which presses asealing body 23 against the transverse web 16 and at the same timecloses the through orifice 17.

The pump piston 10 is provided, starting from the piston part 11, in thedirection of the magnetic part with a two-stage cross-sectionalwidening. The piston part 11 having a small cross section is thusfollowed by an intermediate part 24 with a medium cross section and bythe magnetic part 12 with a large cross section. In the intermediatepart 24, a transverse bore 25 is formed which is connected to the axialpassages 26, 27 of the piston part 11, on the one hand, and of themagnetic part 12, on the other hand.

A first compression spring 28 surrounds the intermediate part 24 and issupported on one side on the step of the piston part 11 having the largecross section. In this case, a web 14 is provided, which advantageouslyensures radial centering of the piston part 11 with respect to themagnetic part 12. Moreover, the two parts 11, 12 have a contact 5 or ineach case an axial contact surface at which the two parts 11, 12 touchone another.

On the opposite side, the compression spring 28 is supported on a stopdisk 29 which is inserted between the armature receptacle 6 and thecylinder part 7 of the pump casing 2.

On the side lying opposite the piston part 11, the magnetic part 12 hasa recess 32, so that a web 15 is formed. A second compression spring 31is supported on the recess 32, the compression spring 31 being heldradially or centered by means of the web 15.

On the opposite side of the compression spring 31, the latter bearsagainst a step 33 of the armature receptacle 6. The armature receptacle6 comprises a stop 30 and is prolonged out of the coil 4 and forms atits end a connecting nipple 34 for the connection of a supply line.

The vibrating armature pump 1 operates as follows.

By the coil 4 being acted upon with alternating current oradvantageously with pulsating or intermittent voltage without a changeof sign, such as, for example, with an alternating voltage comprisingonly one (positive or negative) half wave (that is to say, the otherhalf waves in each case are “faded out”, if appropriate, by means of adiode or the like), the pump piston 10 is set in vibration in the axialdirection A. It in this case vibrates periodically about a neutralposition defined by the compression springs 28, 31 and, if appropriate,also by the compression spring 18.

According to the invention, the two separate parts 11, lie only looselyone against the other during operation, without there being a firm orunreleasable connection. Only the two springs 28, 31 ensure that the twopump piston parts 11, 12 lie reliably one against the other withoutadditional connection measures.

When the piston part 11 penetrates into the cylinder 13, the fluidlocated in the cylinder 13 is displaced. In this case, the sealing body19 closes the outlet orifice of the axial passage 26 in the piston part11. The fluid located in the cylinder 13 consequently attempts to passthrough the through orifice 17 of the transverse web 16 into theconnection piece 20, the sealing body 23 being pressed away from thethrough orifice 17, counter to the pressure of the compression spring22, by the fluid which is put under pressure.

When the pump piston 10 vibrates back into the opposite direction, thepiston part 11 is withdrawn from the cylinder 13. The remaining fluidlocated in the cylinder 13 is in this case depressurized and issubsequently put under a vacuum. The through orifice 17 is therebyclosed by means of the compression spring 22 and the sealing body 23.The compression spring 22 and the sealing body 23 form a nonreturnvalve, by means of which the backflow of the fluid which has justentered the region of the connection piece 20 is prevented.

During the withdrawal of the piston part 11, a vacuum is formed in thecylinder 13 and causes the sealing body 19 to lift off from the outletof the axial passage 26, so that fluid flows through the passage 26 intothe cylinder 13. The liquid or gaseous fluid passes via the inlet nipple34 into the interior of the armature receptacle 6 and through the axialpassage 27 of the magnetic part 12 to the axial passage 26 of the pistonpart 11.

After the cylinder 13 has been filled during the backward movement ofthe piston part 11, the fluid located in the cylinder 13 is once againdisplaced out of the cylinder 13 through the through orifice 17 duringthe forward movement of the piston part 11.

In the embodiment illustrated, the magnetic part 12 lies with its largecross section near the inner wall of the armature receptacle 6. However,the vibrating movement of the pump piston 10 necessitates the cyclicalfilling and emptying of the inner space of the armature receptacle 6 onboth sides of the magnetic part 12. Since, in this embodiment of themagnetic part 12, there is only a very small gap between the magneticpart 12 and the inner wall of the armature receptacle 6, in thisembodiment the transverse bore 25 is located in the intermediate region24, so that an unimpeded fluid flow from one side of the magnetic part12 to the other, and vice versa, is ensured.

However, the function of the transverse bore 25 may also be implementedin another way, for example by longitudinal bores or notches in themagnetic part 12. However, the present embodiment affords the advantageof a high magnetic mass in the region of action of the coil 4.

By the pump piston 10 being spring-mounted on both sides by means of thecompression springs 28, 31, a cushioned reversal of movement takes placein the approach to each dead center during the axial movement, andtherefore no hard stop occurs. Very quiet running of the pump is thusobtained. Furthermore, this arrangement constitutes a mechanicallyvibratory system, so that less energy is required from the coil 4 tokeep the mechanical components of the vibrating armature pump invibration.

By the compression springs 31, 28 being supported on the respectivesteps of the pump piston 10, the compression springs 28, 31 at the sametime form, in conjunction with the extension 32 or the intermediate part24 having a medium cross section, centering elements for the pump piston10.

In a multipart version of the pump piston 10, furthermore, there is thepossibility of a different choice of material between the magnetic part12 and the piston part 11. The choice of material for the piston part 11can therefore be selected with a view to the sealing function, themagnetic properties playing a minor role or even no role at all. Forthis part of the pump piston 10, therefore, magnetic or even nonmagneticmaterials may be used, as required.

It is especially advantageous that a sufficiently high mass of magneticmaterial is arranged in the magnetic part 12 in the immediate region ofaction of the coil 4. The material of the magnetic part 12 does not inthis case have to satisfy any appreciable properties in terms ofleaktightness of the pump, and therefore, for example, a choice ofmaterial with a view to the efficiency or the power of the pump can bemade at this point.

Furthermore, the two-part or multipart form of the pump piston 10affords, in the region of the magnetic part 12, the possibility ofsimple manufacture, for example by cutting the magnetic part 12 tolength from a tubular piece having an appropriate diameter and an axialpassage 27 and composed of suitable magnetic or magnetizable material.

The pump according to the invention is therefore a piston pump 1 with anelectromagnetic drive 4. Single-wave rectification, not illustrated inany more detail, is especially advantageous for operating the pump 1. Anadvantageous rectifier, in particular a diode or the like, is preferablyalready integrated into the pump 1, so that a generally conventionalalternating voltage can advantageously be applied to the coil terminals.In the case of an advantageous alternating voltage with a frequency of,for example, f=50 Hz, 50 voltage halfwaves are generated per second bymeans of the rectifier.

An advantageous voltage halfwave gives rise in the pump 1, above all, tothe following processes:

a) magnetic action upon the pump piston 10:

the current flowing through the coil 4 when a voltage halfwave isapplied generates in the coil 4 a magnetic field which acts aselectromagnetic force upon the piston 10 (large diameter) and counter tothe piston spring 31.

In order to achieve as high a magnetic force action as possible, thecoil 4 is preferably surrounded by a ferromagnetic circuit. Thisferromagnetic circuit is advantageously interrupted in the region of thepiston side against which the piston spring 31 acts by an air gap havinga length of a few millimeters. The two iron parts which may form the airgap are referred to, for example, as pole sleeves and the remainingferromagnetic circuit is referred to as a box-type yoke plate.

As soon as the current begins to flow and the magnetic action of thecoil field becomes greater than the force with which the piston 10 isheld in the position of rest, the piston 10 moves in the direction ofthe air gap. In an advantageous exemplary embodiment, this piston strokein the direction of the piston spring amounts, for example, toapproximately 6 to 7 mm. As soon as the current (halfwave) and thereforethe magnetic force action upon the piston 10 falls or the piston 10 haslargely bridged the air gap, the piston spring 31 is also tensioned tothe maximum.

After the magnetic force action of the coil 4 has largely fallen, thepiston 10 moves in the direction of the piston position of rest again onaccount of the force action of the piston spring 31. The kinetic energyof the piston 10 is so high that the piston 10 moves further alongbeyond the position of rest and is then advantageously braked by thedamping spring 28. For example, this damped stroke amounts toapproximately 3 to 4 mm. The damping spring 28 subsequently moves thepiston 10 back in the direction of the piston position of rest again andsettles into the position of rest again as a function of frictional andfluid damping.

b) pumping action, for example, without counterpressure

The piston 10 has a large and a small diameter. The large diameter isused to bring about force action in the direction of the air gap bymeans of a magnetic field. The small diameter serves as a hydraulicpressure piston 11.

The hydraulic pressure piston 11, in the position of rest, projectsapproximately 8 mm into a compression chamber. This hydraulic pressurepiston 11 is advantageously hollow 26 or drilled open in the middle.This bore 26 is closed in turn by means of a valve 19 and a compressionspring 18 (long).

When the piston 10 is moved on account of the electromagnetic force, thewater located behind the piston 10 (the same side as the piston spring)is advantageously pressed through the large piston bore 27 andsubsequently through the small piston bore 26. During this action, thevalve 19 enclosing the small piston bore 26 opens and the compressionchamber is filled with water.

As soon as the piston stroke has reached maximum and the piston 10begins to move in the opposite direction again on account of the forceof the piston spring 31, the valve 19 located on the piston 10 closes,so that the pressure piston 11 penetrating into the compression chamberdisplaces with its increasing volume the water which is located there.On account of this displacement process, the valve 23 located at thepump outlet opens and the water emerges from the pump 1.

Since the piston 10, on account of its kinetic energy, can move furtheron beyond the position of rest, for example, because of the dampingspring 28, this piston volume penetrating into the compression chamberwill also additionally displace water.

As soon as the damping spring 28 moves the piston 10 in the direction ofthe position of rest again, the valve 23 at the outlet (short spring 22)closes and the valve 19 on the piston 10 (long spring 18) opens, so thatthe compression chamber is filled with water again and the process isrepeated as long as voltage halfwaves are applied to the coil 4.

c) pumping action in the case of a counterpressure of, for example, p=12bar:

As soon as the throughflow is reduced on the pump outlet side, forexample, by means of a throttle, a corresponding counterpressure buildsup at the pump outlet. This counterpressure has the effect that thepiston 10 is displaced out of its position of rest at p=0 bar.

The displacement of the piston 10 is determined by the surface of thepressure piston 11, the pressure acting on the pressure piston surfaceand the counteracting force of the piston spring 31. The higher thecounterpressure, the more the piston 10 is displaced out of its positionof rest at p=0 bar. As a result, the air gap is reduced and thepretension of the piston spring 31 (action of force of the spring 31 inthe position of rest) becomes greater. Since the air gap has becomesmaller and at the same time the spring force greater, when theelectrical halfwave is applied, the piston stroke is no longer, forexample, 6 mm to 7 mm, as at p=0 bar, but is substantially smaller.

The result of the smaller piston stroke is that less water is displacedin the pressure chamber. When the throttle is closed completely, thepiston 10 is moved further out of the position of rest during each pumpstroke until the electromagnetic force no longer enables the pistonspring 31 to be tensioned, and the piston 10 finally comes to astandstill.

List of Reference Symbols

1 Vibrating armature pump

2 Pump casing

3 Yoke

4 Coil

5 Contact

6 Armature receptacle

7 Cylinder part

8 Flange

9 Annular shoulder

10 Pump piston

11 Piston part

12 Magnetic part

13 Cylinder

14 Web

15 Web

16 Transverse web

17 Through orifice

18 Compression spring

19 Sealing body

20 Connection piece

21 Supporting ring

22 Compression spring

23 Sealing body

24 Intermediate part

25 Transverse bore

26 Axial passage

27 Axial passage

28 Compression spring

29 Stop disk

30 Stop

31 Compression spring

32 Recess

33 Step

34 Connecting nipple

1. A vibrating armature pump with a pump casing (2), which comprises acylinder (13) for receiving a pump piston unit (10) adjustableessentially linearly, characterized in that the pump piston unit (10)has at least one separate pump element (11) for pumping the pump fluidand one separate drive element (12) for driving the pump element (11).2. The vibrating armature pump as claimed in claim 1, characterized inthat the pump element (11) has a first stop (5) for the drive element(12) and the drive element (12) has a second stop (5) for the pumpelement (11).
 3. The vibrating armature pump as claimed in one of theabovementioned claims, characterized in that at least one first springelement (28) is provided for acting with force upon the pump piston unit(10) and/or the pump element (11).
 4. The vibrating armature pump asclaimed in one of the abovementioned claims, characterized in that atleast one second spring element (31) is provided for acting with forceupon the pump piston unit (10) and/or the drive element (12), the springforce of the second spring element (31) being directed opposite to thespring force of the first spring element (28).
 5. The vibrating armaturepump as claimed in one of the abovementioned claims, characterized inthat at least the drive element (12) is composed essentially of aferromagnetic material.
 6. The vibrating armature pump as claimed in oneof the abovementioned claims, characterized in that at least the driveelement (12) is composed essentially of high-grade steel.
 7. Thevibrating armature pump as claimed in one of the abovementioned claims,characterized in that at least the pump element (11) is composedessentially of a plastic.
 8. The vibrating armature pump as claimed inone of the abovementioned claims, characterized in that at least onecoil (4) is provided for adjusting the drive element (12).
 9. Thevibrating armature pump as claimed in one of the abovementioned claims,characterized in that a pulsating or intermittent voltage is provided.